1. Field of the Invention
The present invention relates to composite abrasive-articles and a manufacturing method therefor exhibiting high efficiency and long life, the composite abrasive-articles being used for grinding, polishing, and cutting metal, ceramics, stone, or the like.
2. Description of the Prior Art
In general, composite abrasive-articles are used for grinding, polishing, and cutting metal, ceramics, stone, or the like, the composite abrasive-articles being manufactured by dispersing and solidifying a piece of abrasive article consisting of diamond abrasive or cubic boron nitride abrasive and metal powder in a matrix made of resin, metal, or glass of a low melting point.
A conventional method of manufacturing composite abrasive-articles has been disclosed in Japanese Patent Laid-Open No. 50-153387, and another conventional method has been disclosed in Japanese Patent Publication No. 60-3557.
According to these inventions, a sintered body of abrasive and metal powder is pulverized in the manufacturing process so as to be small chips, the thus-obtained small chips being then dispersed and solidified in resin or the like.
In particular, according to the invention disclosed in Japanese Patent Publication No. 60-3557, abrasive and metal powder are incompletely sintered so as to be readily pulverized in the latter manufacturing process. The powder is then screened for the adjustment of the particle size thereof. It then dispersed in resin or metal before being subjected to heat molding so that it is completely sintered.
According to the above-described conventional invention, since massive and pulverized abrasive article pieces are formed by way of the pulverization performed in the manufacturing process after the sintering (the incomplete sintering), it is difficult to employ metal of the type displaying a high malleability and ductility as the metal which forms the abrasive article. Therefore, metal which can be readily pulverized, that is, brittle metal is necessarily employed. According to the invention disclosed in Japanese Patent Laid-Open No. 50-153387, since no particle-size adjustment is conducted, a problem of non-uniform abrasion and surface roughness of the ground surface arises due to the non-uniform distribution of the particle size in the produced abrasive-article obtained after the manufacturing process. Furthermore, according to the invention disclosed in Japanese Patent Publication No. 60-3557, the particle size adjustment of the abrasive which has been pulverized after the incomplete sintering is conducted, the particle size adjustment being conducted by means of a screen. However, the portion separated by the screening raises the cost, and the shape of the screened pieces of the abrasive articles cannot be made to be uniform in terms of the shape thereof. Furthermore, the particle size distribution ranges excessively widely. Therefore, the abrasive-article of the type described above encounters a problem of a difficulty of controlling the grinding ratio, cutting capability, and life thereof.